AutoCodes – GMC – B3978 2015 GMC Sierra

B3978 2015 GMC Sierra Code - Incorrect Environmental Identifier Received from Inflatable Restraint Sensing and Diagnostic Module

Quick Answer

When certain modules are programmed and configured during installation, the module learns a specific environment identifier which is unique to the vehicle. Common causes include Faulty Inflatable Restraint Sensing and Diagnostic Module, Inflatable Restraint Sensing and Diagnostic Module harness is open or shorted, Inflatable Restraint Sensing and Diagnostic Module circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: B3978 2015 GMC Sierra indicates Incorrect Environmental Identifier Received from Inflatable Restraint Sensing and Diagnostic Module.
Common causes: Common causes include Faulty Inflatable Restraint Sensing and Diagnostic Module, Inflatable Restraint Sensing and Diagnostic Module harness is open or shorted, Inflatable Restraint Sensing and Diagnostic Module circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 181

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 19, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code B3978 2015 GMC Sierra Description

When certain modules are programmed and configured during installation, the module learns a specific environment identifier which is unique to the vehicle. The environment identifier is used to prevent the swapping of control modules between vehicles. The Body Control Module (BCM) is the keeper of the environment identifier. The Instrument Cluster, Electronic Brake Control Module (EBCM), Heating, Ventilation, and Air Conditioning (HVAC) Control Module, Inflatable Restraint Sensing And Diagnostic Module, and Telematics Communication Interface Control Module each learn the environment identifier during their configuration process. During vehicle operation, the BCM sends the immobilizer identifier as a challenge and each module responds to the challenge by sending the environment identifier back to the BCM. If the BCM sends an incorrect immobilizer identifier or a specific number of incorrect environment identifiers are received, vehicle starting is disabled.

OBDII Code B3978 2015 GMC Sierra - Incorrect Environmental Identifier Received from Inflatable Restraint Sensing and Diagnostic Module - AutoCodes.com — B3978 2015 GMC Sierra Code - Incorrect Environmental Identifier Received from Inflatable Restraint Sensing and Diagnostic Module

What does this mean?

What are the Possible Causes of the DTC B3978 2015 GMC Sierra?

Faulty Inflatable Restraint Sensing and Diagnostic Module
Inflatable Restraint Sensing and Diagnostic Module harness is open or shorted
Inflatable Restraint Sensing and Diagnostic Module circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B3978 2015 GMC Sierra?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B3978 2015 GMC Sierra code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the B3978 2015 GMC Sierra code?

Need more information on how to fix the B3978 2015 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B3978 2015 GMC Sierra code diagnosed by a professional: Find a repair shop in your area

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B3978 2015 GMC Sierra Code

What does the OBDII code B3978 mean for a 2015 GMC Sierra?

B3978 indicates that the Inflatable Restraint Sensing and Diagnostic Module (SDM) has received an incorrect environmental identifier, which can affect airbag deployment and safety systems.

What are common symptoms associated with code B3978?

Symptoms may include the airbag warning light being illuminated on the dashboard, possible issues with the airbag system, and a lack of deployment in the event of a collision.

What could cause the B3978 code to trigger?

Common causes include a faulty Inflatable Restraint Sensing and Diagnostic Module, wiring issues, poor connections, or problems with the vehicle's onboard communication network.

How can I diagnose the B3978 code?

Use an OBDII scanner to retrieve the code and any other related codes. Inspect the SDM and associated wiring for damage or corrosion, and check the vehicleâ€™s electrical connections for stability.

Is it safe to drive with the B3978 code present?

It is not recommended to drive the vehicle until the issue is resolved, as it may affect the airbag system and overall safety in the event of an accident.

What are some potential repairs for code B3978?

Repairs may include replacing the Inflatable Restraint Sensing and Diagnostic Module, repairing or replacing damaged wiring, and ensuring proper electrical connections are made.

Can I clear the B3978 code without fixing the problem?

Clearing the code may turn off the warning light temporarily, but if the underlying issue is not addressed, the code will likely return, and airbag functionality may still be compromised.

Should I take my vehicle to a dealership for B3978 code issues?

While you can take your vehicle to a dealership, a qualified independent mechanic with experience in airbag systems can also diagnose and repair the issue effectively.

How much might it cost to fix the B3978 code?

Repair costs can vary widely based on the root cause but may range from a few hundred dollars for minor wiring repairs to over a thousand dollars for module replacement.